The present invention relates to a protective respiratory device in the form of a half-mask designed to cover the nose and the mouth of the wearer and combined with a hood designed to enclose the head of the wearer and provided with a visor in front.
It is essential to the function of such protective respiratory devices, as well as devices without a hood, that the mask, whether a full-face mask or a half-mask, is applied in a tight-fitting fashion to the face of the wearer. To this end, protective respiratory devices are usually equipped with elastic and length-adjustable bands, more specifically a first band extending from the two sides of the mask round the nape of the neck of the wearer, a second band extending from the two sides of the mask round the back of the head, and, in the case of a full-face mask, a third band extending from an upper portion of the mask rearwards over the crown of the head to be connected to at least one of the other two bands.
It is true that the elasticity and the adjustability in length of the bands make it possible to adapt a protective respiratory device to fit each particular wearer. However, such adaptation is time-consuming and should preferably be done well in time before use, i.e. not when an emergency arises, which may make people panic, yet necessitating quick application of the device. Especially, this goes for so-called escape hoods, which are intended to be used in the event of a gas emission or a fire and which are a combination of a half-mask covering the nose and the mouth of the wearer, and a hood enclosing the head of the wearer, since the bands for keeping the half-mask in place are often so arranged under the hood as to be difficult of access. Also, prior-art protective respiratory devices often require some readjustment of the length of the bands or their position round the head to be completely tight.